The prior art has proposed a significant number of spacers for use in insulated glass assemblies as well assemblies incorporating the spacers. Generally speaking, in the prior art many of the spacers comprise either metal strips suitably formed into a spacer arrangement or plastic bodies for spacing the substrates. In terms of the metal spacers, U.S. Pat. No. 2,708,774, teaches a multiple-glazed unit where the unit includes a metal spacer which is in direct contact with the substrates. The patentee provides a host of different shapes for the spacer, some of which are purported to absorb stress, etc. between the glass panes. Although a generally useful arrangement, the spacer is in direct contact with the glass substrates and thus a clear thermal bridge is established. The spacer set forth in this reference does not reduce or redirect thermal transmission from one pane to the other via the spacer.
Similar to the above reference, U.S. Pat. No. 4,393,015, issued Jul. 12, 1983 to Kreisman, provides a C-shaped metal spacer which is in direct contact with the substrates it spaces. Mastic material is provided for adhesive purposes between the substrates. The patentee illustrates several alternate embodiments including annular, perannular, rectangular and other such shapes, however, all of the shapes of the spacer directly contact each of the substrates and accordingly, would appear to clearly provide a thermal transmission path from one substrate through the other which, in turn, reduces the energy efficiency of the overall assembly.
Berdan, in U.S. Pat. No. 4,850,175, issued Jul. 25, 1989, provides a spacer tube having a snap-on cap which may be filled with desiccant material. The spacer tube comprises a metal material, however, the degree of contact between the spacer tube and the substrates is significantly reduced in the Berdan tube design. This is an attractive feature from an energy point of view, however, the structural integrity of the spacer is compromised by this feature. The Berdan spacer, when in position between substrates, concentrates all of the force experienced by the substrates at two single flex points. The Berdan arrangement would appear to be susceptible to possible breakage at these bend points under stress over the course of time and may additionally disengage from a respective substrate.
Wampler et al., in U.S. Pat. No. 2,625,717, issued Jan. 20, 1953, provide a multiple sheet glazing unit which incorporates a generally U-shaped metal spacer. Similar to the above discussed references, this reference provides a spacer which would not be adequate for use in a high efficiency insulated glass assembly which additionally permits for pressure absorption. The spacer provided in the Wampler et al. reference comprises a rigid metal member for spacing the glass substrates attached thereto and would not be useful for either interrupting or breaking thermal transmission flow from one pane to the other.
Other references which are generally relevant, but which do not alleviate the energy and structural integrity problems currently existing in the spacer art include U.S. Pat. No. 4,042,736 issued to Flint, Aug. 16, 1977 and U.S. Pat. No. 4,476,169 issued to Nishino et al., Oct. 9, 1984.
In view of what has been proposed in the spacer art, there clearly exists a need for a highly energy efficient spacer assembly which creates energy savings, provides for a higher insulating glass assembly and further which does not compromise structural integrity in view of the aforementioned advantages.